U.S. Pat. No. 4,247,446 describes a fireproof polymer substance based on a reticulated polyolefin containing polyethylene and a copolymer of ethylene and of another polymerisable compound, in particular alkyl acrylate as well as decabromodiphenyl ether and antimony oxide.
British patent application No. 2 041 960 describes a fireproof polymer compound containing polyethylene, a copolymer of ethylene and of another polymerisable compound such as ethyl acrylate, a hydrated metal oxide powder such as hydrated alumina and a coupling agent formed by an organic titanate, in particular isopropyl-tri (dioctylphosphate) titanate or isopropyl-tri (dioctylpyrophosphate) titanate intended to improve its extensibility.
Polymers hardened by reticulation in accordance with U.S. Pat. No. 4,247,446 are very much less elastic than elastomeric polymers and are insufficiently flexible. Further, they are more expensive and more difficult to put into use than non-reticulated polymers, in particular when manufacturing sheaths for electric cables. Those in accordance with British patent application No. 2 041 960 have a very high proportion of hydrated metal oxide which makes them unsuitable for manufacturing sheaths for electric cables by extrusion in industrial conditions.
Preferred embodiments of the present invention provide a polymer compound having high elasticity and high flexibility and which is cheap and easy to put into use in particular by extrusion while being as fire proof as known compounds.